Rondo, have you considered re-doing the corduroy with, say, flannel or alcantara ( a synthetic suede, I think) facings instead of the satin? I think CMcG is right- the buttons are going to make a difference. But I don't think fabric covered. I think maybe dull pewter or bone or antler. If you are going custom anyway, what about moleskin? If you had antler buttons on it, it would look like sturdy, workaday moleskin, a fabric said to have been used for road-menders' trousers. If you had shiny metal ones, it would look like sensuous, suede-like moleskin, a fabric that resembles velvet, without all of the fuss.

Now, you still have to work out the details. Notice how Matt's tweed has a different cuff from KD Burke's. If it were up to me, I'd go with navy or bottle green moleskin, with black piping, also in moleskin or something not very shiny. You might find it not quite formal for some people's tastes, but it would work better on the less dressy end.